SFP-10G-LR vs SFP-10G-SR

What's the difference between SFP-10G-SR and SFP-10G-LR ?
 
SFP-10G-LR 10GBASE-LR SFP Module offer customers a wide variety of 10 Gigabit Ethernet connectivity options for data center, enterprise wiring closet, and service provider transport applications.  
 
Cisco SFP-10G-SR is a SFP+ transceiver that used for 10Gigabit applications,which supports a link length of 26m on standard Fiber Distributed Data Interface (FDDI)-grade multimode fiber (MMF).

Why are you asking the question?  Do you understand multimode fiber (MMF) vs single-mode fiber (SMF)?

http://www.cisco.com/c/en/us/products/collateral/interfaces-modules/transceiver-modules/data_sheet_c78-455693.html

The SR supports multimode up to 400m (though different MMF will support different lengths) while the LR supports single-mode at a length of up to 10km.